Azo dyes



Patented Feb. 14, .1950

AZO DYES William Henry von Glahn, Loudenville, N. Y., as-

signor to General Aniline & Film Corporation, I New York, N. 31., a corporation of Delaware No Drawing. Application April 2, 1946,

Serial No. 659,161

1 Claim.

1 This invention relates to a new class of water insoluble azo dyes. More particularly it relates to azo dyes of the general formula:

In this fprmula R stands for the radical of an aromatic compound containing an azo group and the Xs stand for radicals of the group consisting of methoxy and ethoxy radicals.

These new dyestuffs which can be made in substance or on the fiber have high tinctorial values and exceptional fastness properties. They are obtained by coupling the diazo compound of an amine of the general formula:

wherein the Xs are alkoxy radicals of the group consisting of methoxy and ethoxy groups with an azo compound capable of further coupling and free of water solubilizing groups, such as 'SO'sH and COOH groups. In the production of the dyestufi in substance as a pigment, the 5-chl0ro-2.4- dialkoxy aniline is diazotized in the usual manner and after clarification of the diazo solution it is added to a buffered alkaline solution of the azo coupling component. When coupling is complete, the reaction solution is acidified and filtered. The resulting pigment is then washed acid free and dried. For the development of the color on the fibers, textiles of natural or regenerated cellulose or animal fibers may be employed. Of

benzoic acid, proline, N-methylglucamine or other amino compound known to be suitable for such purpose with a coupling component which is an azo compound capable of further coupling and being free from water solubilizing groups. To this mixture is added sodium hydroxide, Cellosolve, a thickening agent such as starch or gum tragacanth, and water. If desired, such other textile assistants as Turkey red oil, dispersing agents and solvents may also be added. The fabric is printed by application of the paste in the desired design, drying and introducing the treated fabric to an ager where it is subjected for a short time to the action of steam containing the vapors of volatile organic acid or acids, such as formic and acetic acids. As is well known in this type of printing, the acid in the vapor splits the amine stabilizer from its combination with the diazo compound and permits the latter to couple with the azo dye coupling component present in the printing paste. The design is thus developed in the color of the azo dye resulting from the coupling reaction. The fabric is then rinsed, washed and dried. Alternative methods of development may be employed, such as introducing the printed fabric to a bath containing an acid, such as formic acid, acetic acid or oxalic acid, which bath may also contain other assistants and penetrants.

A representative number of azo dyes capable of further coupling is given in the detailed examples below which are intended to be illustrative of the best manner of performing the invention and not as limitations on its scope. In addition to the coupling directive groups, the molecule of the azo dye coupling component may carry any of the usual substituents employed in dye components for enhancement of the dye properties, such as alkyl, alkoxy, nitro and. halogen groups, or it may be otherwise unsubstituted. Unless otherwise stated, the parts are by weight.

EXAMPLE 1 Preparation of a pigment 18.75 grams of 5-chloro-'2.4-dimethoxy aniline are dissolved in grams of water and 23 cc; of 21 B. hydrochloric acid.

Cool this solution to 5 C. and add a solution of sodium nitrite containing 6.9 grams of 100% sodium nitrite for diazotization; when diazotized, add diatomaceous earth and clarify. Add the diazo solution thus obtained to a buffered alkaline solution of 31 grams of 4-(o-nitrobenzeneazo)- l-amino-l-naphthol.

Agitate until coupling is complete.

Acidify with hydrochloric acid, filter, wash acid free and dry. The dyestuiis obtained is a black pigment of high tinctorial value having the chemical formula:

OCH3

EXAMPLE 2 A printing paste is prepared by mixing 2.9 parts of the disodium salt of the =di-azo amino compound obtained by condensing the diazo of short i-time withlivesteam containing the vapors of acetic acid. The developed prints W816 then soaped for five minutes in boiling j soap .solution, r'insedin clear Water and dried. A rich deep black shade 'having good fastness properties was obtained. The dyestulihas the same formula as the dyestuii of Example .1.

EXAMPLE .3

Preparation of a pigment The 'd'iazo of 5 chioro- 2. i di-methoxy aniline is prepared in the same manner as in Example 1. The .d-iazo solution obtained is added to a buffered alkaline solution containing '28 grams of l-(5"- ch'l'o1 o-2' met-h'oxybenzeneazo') resorcinol. Ihe coupling solution is agitated for several hours or until coupling is complete. It is then acidified with hydrochloric acid, filtered, Washed acid free and dried. The dyestufi obtained is a brown pigment having high tinctorial value and good fastnessproper ties. I-ts chemical formula is:

EXAMPLE4 A diazo solution of .5-chloro-2A-dimethoxy aniline is prepared as in Example .1. Add this diazo solution to a buiiered alkaline solution of 26.5 grams of 4-(eechloro 2'-=hydroxybenzeneazo)resorcinol. Agitate this solution for several hours or until coupling is complete. Acidify with hydrochloric acid, .filter, Wash acid .free and dry. The dyestuff obtained is a brown pigment having 4 high tinctorial value and good fastness properties. Its chemical formula is:

OCHs ()H LkH EXAMPLE 5 Prepare .a di'azo solution of 5-ohloro-2A-dimethoxy aniline as in Example 1. Add this diazo solution to a buffered alkaline solution of 31.3 grams of l-(5'-chloro-2-methylphenylazo) -2.3- .di-hydroxynaphthalene. Agitate until coupling is complete. Acidify with hydrochloric acid, filter, washacid free and dry. The dyestuff obtained is a neutral black pigment of excellent tinctorial value having the formula:

(I) C H3 H (I) 0 II Cl 1 CH.O N=N. l

h I 0 H3 EWLE )6 Prepare a diazo solution of 5-chloro-2.4-diniethoxy aniline as in Example 1. Add this diazo solution to a buffered alkaline solution containing 29.7 grams of e-napthylazo orcinol. Agitate until coupling is complete. Acidify with hydrochloric acid, filter, Wash acid free and dry. The dyestuff obtained is a bright brown'pigment'o'fiexcellent 't'inctorial properties having the formula:

EXANIPLE '7 Dissolve 22 grams of 5-chloi'o-2.4-diethoxy aniline in grams of water and 23 cc. of 21 B. hydrochloric acid.

10001 to 5 'C. and add a solution of sodium nitrite containing 6.9 grams 100% sodium nitrite for :d'ianotization. When diazotized, add diatomaceous earthIand clarify.

Add the 'diazo solution thus obtained to a buffered :alkaline solution of 31 grams of -(o-nitrobenzeneazo)-1-arninoflenaphthol. Agita'te until couplin :is complete. Aci'dify with hydrochloric acid, fiit'erywash acid free an'ddry. The'dyestufi obtained is a black pigment of high tinctorial value having the chemical formula:

0 C 11 O H 1| o1 HzN- 'N=N EXAMPLE 8 Dissolve 20.4 grams of fi chloro-z-ethoxy-4 methoxy ani line in 100 grams of Water and '23 cc. oiZlBLhydrochlOric acid.

OE az0)resorcinol. 'Agitate until coupling is complete. Acidify with hydrochloric acid, filter, wash onto N= No, acid free and dry. The dyestuff obtained is a I I 2,497,246 5 6 Cool this solution to --5 C. and add for diazoas defined in the following claim or as imposed by tization asolntion of sodium nitrite containing the prior art.

6.9 grams of 100% sodium nitrite. When diaz'o- I claim:

tized, add diatomaceous earth and clarify. Add he azo dye c po represented by e this diazo solution to a buffered alkaline solution 5 mula of 28 grams of4-(5'-chloro-2'-methoxybenzene- 00H,

brown pigment having high tinctorial value and 10 H2 good fastness properties. Its chemical formula is:

([JCaHs m WILLIAM HENRY VON GLAHN. CHHOONZN OH OCH, REFERENCES CITED 3 1!; 16 The followingreferences are of record in the l file of this patent:

1 UNITED STATES PA'I'ENTS The dyes of this application can be metallized Number Name a Date either in substance or on the fiber by any of th 20 1,872,033 Grether Aug. 16, 1932 usual methods, if it is desired to produce the Laska 1933 metal complexes of the dyes such as the chrome, 2,093,402 Dahlen sept- 1937 copper or cobalt complexes. 7 21135964 Damen 1933 From the foregoing description and illustrative 2,230,099 zwllgmeyer 28, 1941 examples, it will be apparent to those skilled in OTHER REFERENCES the a h t rt t a many and Vamus embwments Friedlander, vol. 6, pages 1297 and 1298, Berlin the invention may be made without departing 904 from the spirit and scope thereof. It is to be un- 1 derstood that no limitations are intended except 

